The advantage of packing replacers into BSA's is, when you register them in the ini, they don't have to be in the data folder!
I have two 10k rpm raptors, with all my biggest (except SI) BSAs at F:/O/xxx.bsa. This has virtually removed loading stutter, moving my bottleneck onto my CPU now.
On last count, by data folder was ~15GB, and my F:/O around 9GB
This top tip I got from Skelton (aka Xuto) a couple years ago
True, and that is definitely not information I would recommend to any newbie. Actually, I would not recommend it at all. If someone asks about it, sure. That is a subject for people really trying to squeeze performance out of their setups... Maybe, if (big IF) someone was running out of space, I would offer that information. It is on the BSAs and Archive Invalidation page on TESIV:POSItive along with the due "It's all on you" warning.